Heretofore, as in the U.S. Pat. No. 3,200,910, in the name of Cunningham and Engle and the references cited therein, brakes of the present general type have been disclosed. This type usually includes at least one, and preferably two, arcuate brake arms pivoted on one side of the drum, extending around to the other side and spring-urged together to apply friction to the drum, and means to separate the arm to release the drum. In the cited prior art it is pointed out that it is important that the feed wheels of partition assembling machines stop quickly where a step, such as a cutting step, is to be performed on the material being fed. If the brake does not stop the feed rolls quickly, the paper may be caused to over-run or back up, ultimately resulting in a partition of irregular size.
The present improvement consists in novel air cooling means for the brake, so that the brake is air cleaned and is air cooled both on its outer and inner parts. The brake drum is provided with fins between the shaft and the cylindrical rim, with air ports adjacent the fins, so that as the drum rotates, air is drawn inside the rim to cool the inside parts of the drum. Then also there are longitudinal cooling fins on each brake shoe, and with two circumferentially spaced compressed air outlets for each brake arm: one outlet in the upper part and the other outlet in the lower part of each. Furthermore, one outlet is on one side of the cooling fin or rib, and the other outlet on the other side. This arrangement gives not only a more complete cleaning of the rotating brake drum, but also a more complete cooling of the outer parts of the drum and the shoes.
Another feature of the invention is that the brake operation itself is employed as a cutoff valve so that it is unnecessary to add external cutoff valves and the timing mechanisms that would be required to cause the air to flow at the proper time.
Also an improved arrangement for operating the brake arms has been provided which simplifies the operation and reduces the number of parts required.